The predictable quantum efficient detector (PQED) is a primary standard of optical power, which utilizes two custom-made induced-junction photodiodes that are mounted in a wedged trap configuration for the reduction of reflectance losses. PQED photodiodes of p-type and n-type were characterized for their dark current dependence on reverse bias voltage at room temperature. As simulations predict that the dark current will decrease exponentially with temperature, the temperature dependence of dark current for the n-type photodiodes was also measured. Two n-type induced-junction photodiodes were assembled inside a liquid nitrogen cryostat. The results from the dark current measurements indicate that the cooled n-type photodiodes are suitable for measuring optical fluxes in the few photon regime. A photon flux of approximately 7,000,000 photons per second was measured using the PQED at a cryogenic temperature with a relative standard uncertainty of 0.15%. The results support the utilization of the PQED as a primary standard of optical power in single and few photon applications.

中文翻译：

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可预测的量子效率探测器，用于低光通量测量

可预测的量子效率检测器（PQED）是光功率的主要标准，它利用两个定制的诱导结光电二极管安装在楔形阱结构中，以减少反射损耗。P型和n型PQED光电二极管的暗电流取决于室温下反向偏置电压的特性。正如仿真预测的那样，暗电流将随温度呈指数下降，因此还测量了n型光电二极管暗电流的温度依赖性。在液氮低温恒温器内部组装了两个n型感应结光电二极管。暗电流测量的结果表明，冷却的n型光电二极管适合在少数光子状态下测量光通量。大约7,000的光子通量 使用PQED在低温下以相对标准不确定度为0.15％的速度测量每秒000个光子。结果支持在单光子应用和少量光子应用中将PQED用作光功率的主要标准。